ML20209C774
| ML20209C774 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/01/1984 |
| From: | Thadani A Office of Nuclear Reactor Regulation |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17083B484 | List:
|
| References | |
| FOIA-86-197, RTR-NUREG-0675, RTR-NUREG-675 NUDOCS 8403190451 | |
| Download: ML20209C774 (3) | |
Text
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MAR 01 94 MEMORANDUM FOR: -Fg_ ;
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Ashok Thadani, Chief Reliability and Risk Assessment Branch
SUBJECT:
ITEMS FOR INCLUSION IN LETTER REQUESTING ASSISTANCE FROM REGION V IN ASSESSING ACCEPTABILITY OF DCNPP SISIP Per your request of February 22, attached is a draft letter of guidance for use by Region V in planning and conducting their verification of acceptability of items modified under P.G.&E.'s Seismically Induced Systems Interaction Program at Diablo Canyon, Unit 1 as required by Section 8.2 of Supplement 11 to the Diablo Canyon SER (NUREG-0675).
l Ashok C. Thadani, Chief Reliability and Risk Assessment Branch
Attachment:
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MEMORANDUM FOR:
R. Martin, Administrator Region V FROM:
Darrell Eisenhut, Director Division of Licensing
SUBJECT:
GUIDANCE FOR VERIFYING ACCEPTABILITY OF MODIFICATIONS MADE UNDER SEISMICALLY INDUCED SYSTEMS INTERACTION PROGRAM Per your request to G. Knighton of my staff, this letter provides guidance to Region V for verifying the acceptability of modifications made to plant structures, systems, and components to resolve systems interactions (SI) identified in P.G.&E.'s Seismically Induced Systems Interaction Program (SISIP) for Diablo Canyon Nuclear Power Plant, Unit 1.
Section 8.2 of Supplement 11 to the Diablo Canyon SER (NUREG-0675) states that Region V will verify the acceptability of any modifications made as a result of the SISIP and the completion by P.G.&E. of those modifications.
To facilitate your inspection we have selected four interactions that were resolved by plant modification from each of these classifications:
(a) Structural, (b) Mechanical, (c) Piping, (d) Electrical Systems, (e) I&C Systems, and (f) HVAC Systems.
These interactions are numbered:
(a) 07-008-001-002 09-004-002-003 32-001-033-005 03-022-001-001
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(b) 06-001-001-006 20-004-001-003 32-001-027-002 15-001=029-001 (c) 22-017-001-001 01-006-001-001 25-200-002-001 18-001-023-002 24-001-118-001 (d) 04-004-001--001 23-012-004-001 24-012-003-001 22-001-001-002 (e) 03-028-023-001 30-001-099-002 06-001-004-007 (f) 23-067-002-001 03-005-002-003 11-007-005-005 25-179-002-001 For each of these interactions review the modification to assure (a) that its design is adequate to resolve the interaction, (b) that it has been L
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MAR 01 134
- implemented as designed, (c) that it fulfills QA requirements, and (d) that its design and implementation do not introduce any new' interactions.
The considerations are:
(a) If the source was modified, it should not subsequently be able to fail in a way as to interact with any target in the vicinity.
(b) Similarly, if the source was relocated, its new location should not allow its failure to interact with any target system or equipment.
(c) If the target was strengthened to resist impacts caused by the postulated interaction, this strengthening should be reviewed to assure that an adequate design basis exists that accounts for effects from all possible modes of source failure.
(d) If the target was relocated, it should not be subject, in its_new location, to interaction with either the original source in any failure mode or with any new source.
(e) If the target was shielded from the source by placing barriers between source and target, the placement and adequacy of such structures should be carefully evaluated.
If sufficient manpower resources are available from Region V we would like to have assistance in sampling the interactions resolved by inspection by the walkdown team and those resolved by engineering analyses.
This would probably involve review of IDS sheets for those resolved by inspection and review of IDS sheets and the P.G.&E. data files for those resolved by analysis.
If more guidance is desired, do not hesitate to call upon my staff.
It is possible for NRR personnel to accompany the inspector during part of his inspection.
Please provide a brief report on the results of your verification.
l Darrell Eisenhut, Director Division of Licensing l
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